Formation of site-controlled and long-wavelength visible light emitting InGaN/GaN pyramidal quantum dots

Abstract

For the recent years, various methods such as quantum dots, defect center, spontaneous parametric down conversion, and atom trap were investigated for single photon sources (SPS) which play an important role in quantum information technology. Among these, semiconductor quantum dots (QDs) also have attracted much attention as an ideal candidate for SPS because of their unique optical and material properties. Group Ⅲ-nitride semiconductor materials cover broad spectral range from ultraviolet to infrared by controlling their alloy composition. In this work, we suggest InGaN/GaN triangular pyramidal QDs as a site-controlled, deterministic and long-wavelength visible SPS for wireless quantum communication applications. Previously, there are many reports on InGaN/GaN pyramidal QDs grown by metal-organic chemical vapor deposition [1][2], but they have failed to generate QDs with their emitting wavelength longer than 500 nm. To overcome this limit, we introduced several approaches including strain engineering and interlayer growth, together with selective area growth for the uniformity of QDs. As a result, we could obtain peak wavelength of QDs longer and made full width half maximum of QDs shaper.